In a process of manufacturing a semiconductor device having a semiconductor linear circuit which is a circuit using a bipolar transistor mainly, thin film resistance elements may be used for the purpose of fine adjustment, etc. of a circuit in the semiconductor device. That is, there is a case where at the final stage of the semiconductor device manufacturing process, thin film resistance elements having desired resistance values are formed in a manufactured circuit and used as a part of the circuit.
FIG. 9 schematically shows an example of the semiconductor device having thin film resistance elements as described above. In this case, thin film resistance elements 130 are formed in a field area which is located above first and second interlayer insulating films 110, 120 covering a semiconductor substrate 100 and in which any element such as a transistor or the like are not formed. In this field area, the upper surface of the second interlayer insulating film 120 is relatively flat, and thus the thin film resistance elements 130 can be formed in the field area so as to have a desired characteristic.
The formation of the thin film resistance elements 130 in the field area as described above causes an increase in the area of the semiconductor device.
In order to avoid the increase in the area of the semiconductor device, JP-A-2002-124639 (Patent Document 1) has proposed that the thin film resistance elements 130 are formed above an area where elements and wires are formed as shown in FIG. 10.
When the thin film resistance elements 130 are formed above the area where the elements and the wires are formed as described above, a step occurs on the upper surface of the second interlayer insulating film 120 shown in FIG. 10. When the thin film resistance elements 130 are formed on the interlayer insulating film 120 having the step, dispersion in resistance value is increased to a non-negligible level.